Network option not coming in dropdown under Property Definition

I have a vRA 7 Setup and Am trying to create a drop down option to choose the vlan while deploying VM from the Blue Print.

For this have created an property Definitions as below.

Then i had created a Property Group as below

Then went to Blue Print Custom Property and added the Property Group and in Custom Property added the VMNetwork

When i come back to Catalog and Deploy a new vm am not seeing any vlan in the drop down option.  instead i see Predefined Value in the drop down menu

Why the Vlan drop down values are not coming up instead the name value comes up.

Where am going wrong. any help appreciated